Sizing composition and glass fibers treated therewith

ABSTRACT

A SIZING FOR GLASS FIBERS, COMPRISING WATER SOLUBLE EPOXY RESINS, AN ORGANOSILANE, POLYVINYL ACETATE COPOLYMER AND A LUBRICANT IS PROVIDED, WHEREBY THE SIZED GLASS FIBERS IN THE FORM OF STRANDS, POSSES EXCELLENT INTEGRITY.

United States Patent US. Cl. 260-40 R Claims ABSTRACT OF THE DISCLOSUREA sizing for glass fibers, comprising water soluble epoxy resins, anorganosilane, polyvinyl acetate copolymer and a lubricant is provided,whereby the sized glass fibers in the form of strands, possess excellentintegrity.

This is a division, of application Ser. No. 25,584, filed Apr. 3, 1970,now US. Pat. No. 3,652,326.

BACKGROUND OF THE INVENTION This invention relates to glass structuressuch as glass fibers in which the surface characteristics of the glassstructure have been modified to enable the glass fibers, in strand form,to be chopped without losing their integrity, while possessing otherfavorable characteristics. Some of the other favorable characteristicspossessed by the chopped strands include: flowability of the choppedstrands during processing, mixing, handling, conveying and moldingwithin a resinous matrix; low bulk density; heat resistance; lightnessof color; and the chopped strands impart high impact strengths toresinous matrices due to a strong bonding relationship between the sizedchopped strands andthe resinous materials, whether thermoset orthermoplastic.

Difficulties in the establishment of a chopped glass strand thatpossesses integrity during processing, flowability during processing,lightness in color and which imparts high impact strengths to resinousmatrices are well known in the art.

From the time of formation of glass fibers to the more distant point intime of their incorporation into a resin matrix to reinforce the same,many processing operations will have had to be carried out. Immediatelyafter the glass fibers are formed and traveling at linear speeds inexcess of 10,000 ft./min. a protective coating is applied to the glassfibers to prevent mutual abrasion. Subsequently, the sized fibers aregathered onto a rotating collection package or routed directly to achopping apparatus where the glass strands are chopped into lengthsranging from "/8 to inches.

When the strands are gathered onto a package it is preferable to dry thepackage prior to positioning the package on a creel with numerous otherpackages,'so that a plurality of sized strands may be subsequently fed'to a chopping machine. When the strands are fed directly to andseparate the resinous coating from the 3,779,981 Ice Patented Dec. 18,73

as a molding compound. Finally the molding compound may be eitherpackaged for subsequent use or may be immediately used in a moldingoperation to form reinforced articles.

The treatment applied to the glassfibers at forming must bemultifunctional for the purposes of this invention. It must be capableof protecting the individual fibers from mutual abrasion, capable ofholding the strand in an integral unit before, during, and afterchopping, capable of exhibiting antistatic characteristics so thatduring handling, conveying, mixing and molding, the chopped strands haveflowability and capable of a strong bonding relationship with a resinousmatrix that is to be reinforced.

Difliculties in the establishment of a strong and permanent bondingrelationship between the surfaces of glass fibers and a resinousmaterial have in general become well known in the art. Because of thenon-porous character of glass fibers, as distinguished from a highdegree of porosity available in natural fibers such as the fibers ofcellulose, wool, cotton, hemp and the like,

penetration of resinous materials into the fibers is not available foruse in establishing a bonding relationship between such glass fibers anda resinous material. Because glass fibers naturally form into elongaterods having very smooth surfaces, as distinguished from the roughsurface characteristics of natural fibers, a gripping relationship or amechanical bonding is difficult to establish between resinous materialsand the untreated glass fiber surfaces. Thus a physical anchorage of thetype relied upon chiefly for the establishment of a bonding relationshipbetween natural fibers and resinous materials is not capable of beingdeveloped with glass fibers. Glass fibers may be etched or roughened topresent a surface of some porosity but desirable strengthcharacteristics of the glass surfaces are simultaneously lost.

In the absence of the ability to make use of physical forces in bonding,it becomes necessary to rely upon the development of a relationshiprequiring chemical bonding or physical-chemical forces based uponmolecular or ionic attraction and the like. With synthetic resinousfibers e.g. nylon, polyester, etc., a strong bonding relationship can bedeveloped with the smooth surfaces be cause such fibrous materials areresinophilic in character and therefore are preferentially receptive toresinous treating materials. In addition, the resinous materials, ofwhich the fibers are formed, have the ability of being softened by heator solvent in a manner to enable the development of a desired bondingrelationship with the applied treating material. Such chemical forcesresulting from the softening of the synthetic fiber surfaces are notavailable with glass fibers because the glass fibers are inert to heatand solvents and because the glass fiber surfaces are dominated bygroups that are hydrophilic in character and therefore receive moisturein preference to resinous materials. As a result, only a weak bondingrelationship is capable of being established in" the first instance and"even this limited bonding is reduced in the presence of moisture orhigh humidity sulficient to cause a moisture film to form glass fibersurfaces with a moisture interface. 1. 2

When 'a strong-bonding relationship cannot be; established betweenglass. fibers and a resinous material used in combination therewith,maximum utilization. of the strength properties of the glassfiberscannot be made available in the products that are formed.Evenwhere ;.a fair bonding relationship between glass and resin can beestablis ed. u de xtrere ly properties of the glass fiber reinforcedplastic composite depreciates greatly under high humidity conditions orin the presence of moisture.

When glass fibers are formed into strands, containing many fibers, andthe strands are subsequently chopped into lengths of from about inch toabout inch, it is desirable to have the chopped strand possessintegrity. That is, after chopping it is desired to have the strand in arod-like manner without the many fibers making up the strand separatingfrom the rod-like structure. The desirability of this rod-like structureis important when a resinous matrix is to be reinforced with glassfibers to improve strength and other characteristics. Another desirablecharacteristic of the chopped strands of this invention is that theyhave a high degree of flowability during processing, especially withinthe resin matrix that is to be reinforced so that the chopped strandshave a uniform dispersement within the matrix and not be heavily groupedin one local concentration and void of chopped strands in anotherconcentration.

It is therefore an object of this invention to produce a treatment forglass fibers and to produce glass fibers treated with a material toenable the glass fibers, in strand form, to be chopped without losingtheir integrity during processing.

It is another object of the invention to provide a new and improvedcoating for glass fibers so that the coated fibers, when gathered into astrand, chopped, and subsequently used as a chopped reinforcement inresinous matrices, remain flexible and substantially insoluble in thematrices.

It is another object to produce glass fibers, which when chopped,possess good flowability characteristics during processing.

It is still another object to produce glass fibers, which whenincorporated with a resinous matrix, exhibits a strong bondingrelationship with the matrix.

Further objects and advantages of the invention will become apparent tothose skilled in the art to which the invention relates from thefollowing description.

Flowability of chopped strands becomes extremely important during theintroduction of the treated strands to the chopper. It is desirable toobtain chopped strands of uniform length, but this becomes ditficultwhen the chopper becomes clogged with previously chopped fibers. Staticforces are set up on chopping and must be combated.

The lack of strand integrity during processing is more than a problem.It is detrimental to the uniform distribution of chopped strands withina resinous matrix because the strands agglomerate or clump together.When a thermosetting matrix is to be reinforced, a premix, comprisingthe chopped strands and the resin, is formed. When a thermoplasticmatrix is to be reinforced, the chopped strands and resin are introducedinto an injection molding machine as a dry blend via vibration. Iffilamentation of the chopped strands occurs, the strands will tend tostick together through physical or static forces, and cause anon-uniform distribution of the strands into the matrix, or anon-uniform distribution of ,the strands .into. the injection moldingmachine. V

. The, de ee of inte ri ossessed b th ho d gr g W p y e c ppe ected toconcentrated loads, to allow a yielding of the strands becomes extremelyimportant when the strands are incorporated with a resinous matrix.Duringthe in corporation it is desirable to obtain some filamentizing ofthe strand s'ufiicient' to increase the surface area of avail ablereinforcement, but 'insuflicient to be incapable-of actualreinforcement. It has'been found that when the strands have'no'deg'ree'of filamentation upon incorporationwith ar'esi'nous'material, strengths of theboi'nposite are low. The "samephenomenon is present when there is no integrity of the chopped strandafterinc'orporation 'of thestrandwith' the resinous matrix. Therefore, acompromise between a highly integrated strand and a highly dryconditioner, .the stljength V filamentiz e d strand must be reached.Chemical as well as physical forces contribute to the degree offilamentation of the treated strand, after incorporation into a resinousmatrix.

The inventive treatment, hereinafter described in greater detailprovides all of the advantages as above described.

SUMMARY OF THE INVENTION According to the present invention it has beendiscov ered that'impact strengths of resinous matrices reinforced byshort lengths of glass fibers are greatly increased if the short lengthof fibers are in the form of a strand hav-' ing some degree offilamentation, rather than dispersed throughout the resin as individualfilaments or small groups of filaments. The inventive treatment whichbonds the fibers together into a strand is of low or intermediatemolecular weight, so that it is flexible, but is crosslinked to arelatively insoluble degree and capable of holding the fibers togetherin the form of a strand during processing. Residual reactivity of thetreatment provides a controlled bonding between the treatment on thestrands and the matrix resin.

According to the invention, the film former within the treatment iscapable of partial reaction during the fiber forming operation to forman integral strand and it is capable of further reaction whenincorporated in a resinous matrix, to provide a controlled degree ofattachment between the surface of the fibers and the matrix resin. Thecoating on the fibers is generally immobile or in a solid state, and thedegree of bonding which is achieved between the strand coating and thematrix resin is a limited or controlled one, which allows the bondbetween the strand and the matrix resin to yield under a concentratedload, such as occurs during impact. Concentrated loads cause some ofthese bonds to be broken to allow the strand to move. It appears thatsome'degree of filamentation of the treated strand is necessary uponincorporation of the strand with the resin matrix so that a synergisticsystem is developed.

In a preferred form of the invention, individual glass fibers are coatedat forming with a water dispersion comprising a low or intermediatemolecular weight polyvinyl acetate copolymer, a metal acid catalyst, anda combination of epoxy resins modified to act as lubricants. After theindividual fibers are coated with the dispersion, they are gatheredtogether into a strand and collected on a package and dried at atemperature which causes the polyvinyl acetate copolymer to crosslink.The crosslinking of the polyvinyl acetate copolymer causes the coatingto set up sufficiently, so that it is flexible but substantiallyinsoluble in a solution of matrix resin. The matrix resin may be astyrene solution of a crosslinking polyester resin, or may be an organicsolution of some other unsaturate such as polypropylene, polyethylene,or polystyrene. When the coated strand is mixed with the matrix resinand cured at a temperature above the drying temperature employed atforming to crosslink the coating material, a polymerization of thematrix resin is produced, and a limited number of bonds are formedbetween the surface of the strand coating and the matrix resin. Thelimited number of bonds between the solid coating material and thematrix resin becomessequentially broken when submatrix resin relative tothe strand, and a consequent redistribution of the load over a number ofstrands. In addition, the coated strands are locked into the resinInatrixmechanically upon polymerization of the resin matrix. Aconsiderable improvement in impact strength is therebyproduced.

' The metal acid catalyst or Lewis Acid is selected from a. generalclass of soluble metal salts of the transition 1 metals. These includealuminum, calcium, titanium, vanadnim, chromium, manganese, iron,cobalt, nickel,

copper, zinc and strontium. Metal chlorides such as AlCl and metalnitrates are the preferred metal salts.

Y DESCRIPTION OF THEPREFERRED; EMBODIMENTS I EX kMPLE I A sizingcompjosition comprising an aquasug dispersion of the following materialsis prepared as follows:

proximately 1,500 parts by weight of the general type of .epoxide shownbelow, having an n of 3.6 with 1,500 parts by weight of diacetonealcohol in a 4-liter Pyrex reactorlcettle having a motor drum agitatortherein and surrounded by a Glas Col heated mantle-controlled by aVariac. Y a

The in or the finished size should be from about 4.0 to about 5 .0. H HV .EXAMPLEII An aqueous dispersion is made of the following materials:

. pH of the dispersion should be approximately 4.5.

The materials were mixed together by combining acetic acid with epoxiesA, B, and C. The resinous mixture was heated to 120-140 F. and thencool, deionized water (45-65 F.) was added slowly to the heated mixturewith thorough and vigorous agitation (Lightniu mixer is suitable) .untilthe resinous mixture inverts from a slightly viscous to a. highlyviscous'state. Upon inversion, an additional gallon of water is added.This mixture is agitated L for about ten minutes and fiurther dilutedwith twenty gallousof water. Subsequently, polyvinyl acetate copolymer,iAlCl i gamma glycidoxypropyltrimethoxysilane and the paintable siliconfluid emulsion'are added to the mixture. Additional water is'added inorder to adjust the solids of the mixturefrom about 6.0 to about 12.0percent.

if Epoxy A.-This material is prepared by dissolving ap- HO-CH;-CH1 CH;

.HQ- Hi-c ,1 p I a The vessel is suitably closed OE, and is profidedwith a reflux condenser to prevent the escape of solvents and/orreactants. Approximately 64 parts by weight of diethanolamine is addedwith mixing. The temperature is raised to C. with continuous mixing andheld at 100 C. for one hour to provide ample time to react all of theamine. The material produced by the above reaction was essentially thatindicated by the following formula, having a single terminalsolubilizing group at one end:

Epoxy B.This material is prepared by dissolving approximately 805 partsby weight of the general type of epoxide indicated by Structure I havingan n of about 3.6, with 345 parts by weight of xylene in a 2-liter Kimaxreactor kettle having a motor driven agitator therein and surrounded bya Glas Col heated mantle controlled by a Variac. The vessel is suitablyclosed 011, and is provided with a reflux condenser to prevent theescape of solvents and/or reactants. The mixture is heated to C. withstirring to thoroughly dissolve the resin and thereafter the temperatureis raised to C. and approximately 65 parts by weight diethanolamine isadded slowly with continuous mixing. The products are held atapproximately 120 C. for about one hour to provide ample time to reactall of the amine. The material produced by the above reaction isessentially that of Structure II shown before, and contains apreponderance of molecules having a single terminal solubilizing groupat one end.

Thereafter a polyglycol monoester, such as a polyglycol monooleate, isadded and reacted with the remaining oxirane groups. Approximately 400parts by weight of a commercially available polyethyleneglycolmonooleate having a molecular weight of about 400 is added to thereaction kettle using about 2.5 parts by weight of a basic catalyst (asfor example potassium carbonate), and the mixture heated to maintain 120C. for four hours. The resulting material has an epoxy equivalent of3,000, indicating one epoxy equivalent for 3,000 gms. of the material.The material produced by the above reaction is shown by the followingformula showing the preponderance of molecules that have terminalsolubilizing groups at both ends of the molecule:

CH3 1 0H L is .1.

wherein x=8 to 10.

Epoxy C.'-This material is prepared by dissolving 'a'p- Amatrix-resin'mix was mfade frorn th'e following inproximately 530 partsby weight of the general type-of gredients: $33 51' ii epoxide indicatedby Structure "I having an n of about A 3 a; 3.6 with 390 parts of xylenein a 3-liter Pyrex reactor g t d 1 l t 1 25: weight kettle having amotor driven agitator therein and "suraiih i fiii f i g i rounded by aGlas Col heated mantle controlledby a 5 g g' .gf g s Variac. The vesselis suitably closed off, and is provided PEOPY 3 3 g 93 5; Hum er with areflux condenser to prevent the escape of solvents Q 1 30*? d i 0styrene 2011 0 and/or reactants. The mixture is heated to 105 C. with Tf b t I 1 stirring to thoroughly dissolve the resin, and therea t :3 g ggz enzoa e the temperature 18 raised to 120 C. and approxlmately Zincstearate 800 43 parts by weight of diethanolamine is added slowly withcontinuous mixing. The resin mix was produced by charging the polyesterThe products are held at approximately 120 C. for resin to a Cowlesmixer, and thereafter slowlyjaddin'g about one hour to provide ampletime to react all of the the other ingredients while the mixer wasrunning to amine. The material produced by the above reaction isthoroughly disperse the ingredients throughout the resin.

essentially that of Structure 11 shown before, and con- A molding premixwas made from the following intains a preponderance of molecules havinga single tergredients: 6 minal solubilizing group at one end. e V Y 1 ve Thereafter a polyglycol monoester, such as a poly- 20 gfgii' mix s ffgglycol monooleate, is added and reacted with the remain- Calciumg'l'iig' i 'g 315'0 ing oxirane groups. Approximately 720 parts byweight Clay finer 7 v ".f'f' 2832'0 of a commercially availablepolyethyleneglycol monoinch 1 1 22 "gg gaag'g g 'ai gv'E% oleate havinga molecular weight of about 1,500 is added glass) 1080 0 to the reactionkettle using about 2.5 parts by weight of 25 u a basic catalyst (forexample potassium carbonate) and The molding PIeIIliX Was de by addingthe're sin the mixture heated to maintain 120 C. for four hours. to aBaker-Perkins g ha h lyli mixer, t The reaction vessel is cooled toabout 200 F. and about addmg the y d the a m carbonate fi lers wh e 100parts of diacetone alcohol or other polar solvent is the mlXeI wasfllhhlng- After the above mgredlehts were added and this solutionstirred while cooling to room dispersed in t resin, the mixer s r r a dtemperature. The material produced by the above reactional 6-8 minutesto assure a uniform dislp tfl i v E tion is shown by the formula showingthe preponderance after, the quarter inch pp Strands e de in ofmolecules that have terminal solubilizing groups at during a 30 Second pand the mixer Was T1111 for both ends of the molecule: an additional oneand one-half minute period to assure Ho-crn-om OH om OH on, t onHO-CHr-CH: l OH; I., om l wherein x=28 to 36. a uniform dispersion ofthe strand throughout the mix- The paintable silicon fluid emulsion iscommercially tur of other in redients, The chopped strands showed aavailable under the trade name SM-2050 from General slight degree offilamentation after mixing, which, is a Electric Company. Thegamma-glycidoxypropyltrimethdesirable characteristic ofglass strandstreated (according oxysilane is commercially available under the tradenames to the inventive concept. t I A-187 and Z-6020 from Union CarbideCorporation and The chemically reactive polyvinyl acetate. copolymerDow-Corning Corporation respectively. The polyvinyl undergoes a highdegree ofcross-linkingtherebyproducacetatezN-methylol acrylamidecopolymer emulsion is ing a tough, hard coating on the glass fiberstrands that commercially available under the designation 25-2828possesses a highly insoluble characteristic with a resinous fromNational Starch Company. The AlCl is commercialmatrix. The insolubilitycharacteristic becomes extremely 1y available under the designation42-2301 from National important when preparing a premix compound and/or.Starch Company. when an injection molding machine is used becau'sefi tEight hundred sixteen continuous filament glass fibers controls thedegree of filamentation .of glass filaments approximately 0.00050 inchin diameter were produced from the strand into a multiplicity ofdiscreet bundles," by attenuating molten streams of glass at a rate ofapsmaller in diameter than the original strand; Some file: proximately10,000 feet per minute. The glass fibers, immentation is desirable buttoo much or too little is 1111;" mediately after solidification, werepulled over a graphite desirable. This desirability has beenprovenbyboridudt-l, applicator that was flooded with the aqueous dispersioning impact tests upon the reinforced'structures. Analysis given above.The coated fibers were brought together into shows that impact strengthsare greatest when there is a strand by the applicator, and the strandwas then wound some degree of filamentation of the glass filaments fromon a rotating drum mounted on a revolving spindle which the strand. jpulled the fibers'at a rate of approximately 10,000 feet In addition "tothe chemically reactive polyvinyl acetate per minute. A suitabletraverse mechanism moved the copolymer, the combination of special epoxyresins,.usec l strand back and forth across the drum to produce a coiledin the treatment that coats the glass filaments, functions packageapproximately 12 inches wide, with an inside dias a lubricant betweenthe filaments that make up the ameter of approximately 8 inches, anoutside diameter glass strand. This characteristic becomes extremelyimof approximately 12 inches, and tapered sides. The packportant whenthe glass strand is unwound from the dried age was removed from thespindle and dried in an oven at forming package prior to going to thechopper. Apparenta temperature of about 265 F. for approximately 8 toly, the combination of epoxy resins allows the polyvinyl 20 hours.Thereafter the strand was unwound from the acetate to Cross-link On thestrand during drying but package and chopped into one quarter inchlengths. prevents cross-linking of the coating from strand to "strand tostrand on the forming-package. Without this gathering 'theglass fibers,subsequent-to applying" the l I i yj t b iqs i iq; there a slightstrand-tQ-St fi "sizing, intof the form of a"strand;collectitig the'strand bonding on the package,-suflic1ent m-stren'gth that upon onatpackage; n e tiand ifidinth-vipabkhg .saturated polyesters andpolyolefins, and said sizing hav- 20 removal of the strand from thepackage,- the strand separates from itself thereby destroying itsintegrity, and furthermore causes fuzzing and broken strands. When 5Short lengths drymg the pp St ds to part ally cure the integrity of thestrand is destroyed, the advancing the sizing material suflicifiint Imaintain Strand integrity strand at the chopper tends to foul thechopper thereby durmg Subsequent Processmg; Incorporating the chopped achopping machine; chopping the strand into uniform cutting down on thechopper efiiciency and the uniform dried strand into the resin matrixwith suflicient agitation ity of the length of chopped strands. to helpsubdivide the chopped, dried strands into the I claim: smaller bundles;and curing the resin matrix and the A fnethod of Rroducing h impacfisfrength glflss bundles of glass fibers coated with the partially curedfggf fig giz g g f gggg 4 1 5535 fg g ig sizing so that the bundles ofglass fibers are mechanically fibers substantially immediately afterforming, said sizing 15 held and chemlcany to e mamx' being capable ofpartial reaction during drying to main- The fnethod as claimed clam 1Wherem upon tain integrity of the glass fibers in the form of a strandIncorporating the pp dried Strands into e res n and said sizing'b'e'ingcapable of further reaction with matrix, the agitation is sufl'icient tocause filamentation a matrix resin Selected fI'QIII the gfOuP consistingOf 1111' of the strand into smaller bundles of glass fibers to incr th fce r d h mg suflicient msolubihty with the matrix resin so that ease 6sm a a ea an t e eflecuveness of the Slzed the stran is subdivided intoa plurality of smaller bundles glass fiber's as a reinforcement butlusuflicient to f of glass fibers and said sizing comprising in percentby filamentatlon to decrease the effectiveness of the sized weight:glass fibers as a reinforcement.

Epoxy A, having the following formula:

0.1-2.0 (active solids) HO-CI-Ir-CH; I O H CH: OH CH: O

\N CH, tncmiomnnmsacmlo+Mmnsscm HOCH2C i L CH1 in CH:

wherein n=about 3.6

Epoxy B, having the following formula:

. 0.1-3.0 (active solids) wherein 21552810 36, and wherein n=about 3.6

Glacial acetic acid: 0.1-0.5 i 3. The method as claimed in claim 1wherein the sized Paintable f fluid 7 strand is dried on the'pac-kageprior to feeding the strand Gamma-glycidoxypropyltrimethoxysllane.0.05-0.8 from the package to chopping machine;

Polyvinyl acetate: N-methylol acrylamlde copolymer (active solids): 3.010.0 f- 9 as 1 e es F Ionic solution of A101 (active solids): 3.0.0-0.36smug 1s dried on the glass fibers m o qpp s .t

Deionized water: Balance strand into uniform lengths. g r

"53A inethodof' producing ahigh impactstreng'thglass fiber reinforced.resin composite comprising: applying a sizing. composition 1 to glassfibers having, thefollowing compositionyin percent by weight:

v I Lhaving the following formula:

1 0,38 (active solids) HO-CHr-GIQ -N-omno-om-om wherein niiabout 3.6Epoxy B, having the following formula:

1.7 (active solids) wherein w=8 to 10, and wherein n=about 3.6

Epoxy C, having the following formula 0.19 (active solids) Glacialacetic acid: 0.16

Paintable silicon fluid emulsion: 0.30

Gamma-glycidoxypropyltrimethoxysilane: 0.40

Polyvinyl acetate: N-methylol acrylamide copolymer (active solids): 6.60

Ionic solution of AlCl (active solids): 0.18

Deionized water: Balance Epoxy A, having the following formula 0.1-2.0(active solids) wherein nzabout 3.6

Epoxy B, having the following formula:

0.1-3.0 (active solids) HO-CHr-C 3 wherein 0:8 to 10, and wherein at:about 3.6

Epoxy C, having the following formula 0.1-2.0 (active solids) wherein m:28 to 36, and wherein n=about 3.6

gathering'the sized fibers into a strand; chopping the strand intouniformlengths of from /8 inch to about 1 inch; drying the choppedstrands to partially cure the sizing-,in situ; on the glass fibers tomaintain strand integrity until thestrandsare incorporated with a resinmatrix selected from the group consisting of unsaturated polyesters andpolyolefins; combining and dried, chopped I 12 strandwith a resinmatrix" with sufiicientagitation until a slight degree' of filamentationof the integral strandinto smaller bundles occurs; and curing the resinmatrix about and to the dried bundles of glass fibers.

on. i on C a I on, OH

Wo-om-im-om Glacial acetic acid: 01-05 70 Paintable silicon fluidemulsion: 0.1l.0 J

Gamma-glycidoxypropyltrimethoxysilane: 0.050.8 Polyvinyl acetate:N-methylol acrylamide copolymer (active solids): 3.0-10.0 Ionic solution'of AlCl (active solids): 0.06-0.36 75 Deionized water: Balance whichsizing is capable of being advanced to a partially 8. The method ofclaim 7 including the step of mixing cured state so that the sizedstrand is generally insoluble from 1 to 30 percent by weight of thecoated strand with in said predetermined solvent, said sizingcomposition and from 70 t 99 Ptlfctfllt y Weight of a Solution of ansaid matrix resin being bondable, drying the sizing comunsaturatedPolyester resin- 9. The method as claimed in claim 7 wherein the resinmatrix further comprises free radical catalysts, mold release agent andinert fillers.

10. The method as claimed in claim 9 wherein the resin matrix comprises:

position on the strand to the partially cured state to bond the fiberstogether to maintain strand integrity during subsequent processing,chopping the dried strand into uniform lengths, mixing the choppedstrand with the matrix resin and the predetermined solvent, untilsufficient filamentation of the partially cured sized strand occurs to10 Ingredients: Percent by weight reduce the integral strand into aplurality of smaller Unsaturated Polyester @5111 9 ph h 1 c bundles ofglass fibers and curing the matrix resin in situ anhydrlde': 1 mol11131610 anhydrldel 2 H 5 propylene glycol cooked to an acid numberaround and to the partially cured sizing composition on of 30-35 anddiluted with 30% styrene solthe chopped bundles of glass fibers.

vent) 2011.0 7. The method of pr g high lmilact Strength Tertiary butylperbenzoate 13.2 glass fiber reinforced resin bonded compos1tes,compris- Benzoyl peroxide 6 o ing: forming glass fibers; applying anaqueous dispersion Zinc Stearate of a sizing composition to the glassfibers, said sizing calcium carbonate 337,1 composition comprising inpercent by weight: Clay 3389.9

Epoxy A, represented by: 0.1-2.0 (active solids) HO-CHz-CH: OH OH: OHCH3 0 l i I N OH; H CH1 0 O CH: H-CHg-O O-CHz-CHCH; HO-CH2 H: L CH: J11CH3 wherein n: about 3.6

Epoxy B, represented by: 0.1-3.0 (active solids) HO-GHa-CH; OH

on, on cm on r r-onl-dn-onlo--l--o-onlhn-onl o--l--o-cm-dn cm L CH: .JnCHa wherein 0::8 to 10, and wherein n: 3.6

Epoxy '0, represented by: 0.1-2.0 (active solids) HOCH1C|H2 OH I- CH3 OH"I on, OH

N-cnl-t ln-om-o-l--o-cnr-dH-cHl-0-;i-0-oHl-dH-cm HO-CH -H; CH; In H, 10CHz-CI-Iz o-o-(cHm-om L |x wherein (0:28 to 36, and wherein n=about 3.6

Glacial acetic acid: 0.10.5 Paintable silicon fluid emulsion: 0.1-1.0Gamma-glycidoxypropyltrimethoxysllane: 005-08 and wherein the choppedglass fibers are present in an Polyvinyl acetate: iN-methylol acrylamidecopolymer (active solids): 3-0400 amount of 1292.8 parts by welght.

Ionic solution of AlCl (active solids): 0.06-0.36

Deionized water: Balance References cued gathering the sized fibers intoa strand; heating the strand U I STATES PATENTS sufficient to partiallyreact sizing, in situ, on the strand in order to maintain an integralstrand through further gii 260 41 AGUX processing, but substantiallyinsufficiently to completely m AGUX bond the glass fibers in the strand,so that the strand 3,143,405 8/ 1964 g 117126 GBX will lose someintegrity upon mixing with a resin matrix 3,334,166 8/1967 Marzocchi264136 selected from the group consisting of unsaturated polyesters andpolyolefins; chopping the strand into uniform LEWIS T. JACOBS, PrimaryExaminer lengths; mixing the chopped strand with the resin matrixwhereupon the integrity of the strand is subdivided into a multiple ofdiscreet smaller diameter bundles of glass 117 126 260 34'2 37 EP 41 AG830 W fibers; and curing the composite to bond the resin matrix aboutand to the discreet smaller diameter bundles of glass fibers.

